The only additives I've found addictive are those that can be put into homemade food as well, though often homemade food has a less addictive ratio of these additives.
The additives I mean are fat, salt and sugar.
After reading the book "The End of Overeating," it really hit home to me that the most addictive foods had all three ingredients - and how addictive a food was depended on those three elements, not who made them.
It is true that processed foods are designed to be "addictive," but no one (including the food companies) think if it this way. The word we use instead of addictive is "yummy."
Food companies (as well as sweet cookie-baking grandmas and anyone who makes food for others) want to make their food taste good - so good that it leaves people wanting more, and more and more. So people say "this is the best thing I've ever eaten (or at least this is better than anything else like it).
Food companies tend to be better at this "must eat more" factor than most (but not all) home cooks, but I think don't think it's "conspiracy" so much as a knowledge of human nature "If we want people to want this, we need to make it really, really good."
And billions of years of evolution has bred into the omnivore and herbivore (and perhaps even many carnivores) that a food that is rich in salt, fat, and sugar is a nutritional "goldmine" (because in the natural world it is - try to think of a natural food that contains all three nutrients, salt, fat, and carbohydrates). So our instincts say "eat as much of this as you can, because you're not going to find something so awesome again."
In the natural world calories are rather hard to come by, a food that combines these three nutrients (two macros and a mineral) would be a boon to survival not a detriment. And stress (such as even the stress of repeated dieting) actually makes animals (and humans) more prone to overeating these foods (for several reasons. This food combination actually releases stress-relieving endorphins, and stress itself actually burns calories that wild critters cannot spare...
Processed foods should be avoided for so many reasons, and "addictiveness" is one of them - but you need to know why they're so addictive, so that you don't find yourself just making your own "drug" at home.
Some foods (I find) are actually MORE addictive in their home-made forms (mostly because the food companies haven't been able to duplicate the addictive-yumminess factor of the homemade).
Baked goods in general, but brownies specifically. I've never had a mass-produced brownie that inspired me to eat the whole box in a day. Homemade brownies (especially while still warm) those are crack to me (and really about the only "dessert" sweet I have no control over). They have to have a crispy top, chewy edges, and a gooey center. The flavor and texture have to be "just perfect" for me to want more and more - and assembly-line brownies just aren't that perfect storm of flavor and texture.
I highly recommend "The End of Overeating" because it really explains how and why mass-produced AND some homemade foods can be addictive.
It helped me realize that the salty/sweet/creamy/fatty/crunchy/chewy texture and flavor profile was the addictive element, and recreating the product at home actually made the situation WORSE (because I can make a brownie better at home than Hostess can).
It didn't help me to stop buying from my drug dealer only to build my own meth lab at home.
I can "cheat the dealer" to some degree, and still get some of the "high" of the flavor combo, by eliminating one element of the trio. I usually eliminate fat, because it's the element with the most calories. To combine sweet and salt for example, I'll sprinkle apple slices with just a tiny amount of sea salt.
The sweet/salty flavor combined with the crunch (I love super crisp apples for this) is super yummy without inspiring the "need more, need more, need more" instinct kicking in.